Resident NZTrailRun Nutritionist Alice Sharples gives the low down on LCHF diets and the benefits to endurance athletes

My NZTrailRun.com blog

Hello my name is Alice and for me blogging is a way to educate people on health, nutrition and well-being. I intend to use

NZTrailRun.com as a platform to educate on the latest findings, trends and also controversial topics that will get you thinking, disagreeing or maybe even trying new ways to optimise your performance. Well-chosen foods help athletes train hard, reduce risk of illness and injury, and achieve performance goals, not matter what the level. Unless you are running like Mo Farah in the 10,000m or 5,000m why would what he ate be relevant to you? Elite athletes, companies and also un-educated individuals give nutrition advice based on their own knowledge that is not specific to you. Each individual needs their own nutrition strategies based around their needs, lifestyle and goals to ultimately enhance their performance.

High-Fat Diet or LCHF

My first topic is controversial. I thought why not throw something out there, get people thinking. No use to you if I’m just writing about boring old topics we have all heard time and time again.

There is a lot of unknown but also a lot of success shown by using this diet. Done right, with the right information behind you, adapting your body to a high fat diet may lead to endurance success.

Supplying energy to the muscles while running is a key factor for success in endurance events. An endurance athlete’s diet must provide the muscle with adequate fuel to achieve ideal adaptations for performance benefits. In other words you wouldn’t put diesel in a petrol car, so why would you give your muscles the wrong fuel to run on?

There have been many debates around the use of fat in endurance training. The debate was started due to carbohydrate depletion being a major cause of fatigue in endurance events. In attempt to delay the onset of tiredness, specialists started looking at the use of fat to increase endurance capability but had mixed results. Some athletes showed massive improvements, while some showed none, or some studies even showed negative performances. But if we look at the way fat is used in endurance exercise as well as the effect that endurance training has the body, a high fat diet should theoretically increase someones endurance.

Here are some interesting facts surrounding the high fat diet:

Fat is a highly concentrated energy storage form and contributes about 90% of the body’s energy stores compared to carbohydrate contribution of about 2%! Fat should be able to give our bodies a generous amount of fuel over a long period of time.

The muscles’ main fuel source is fat for low to moderate intensity exercise over long time periods.
Exercise stimulates the breakdown of fat and the fat is then transported to the muscle to produce energy. This process is slow and energy is only produced after about 30 minutes of exercise.

As the time you are exercising increases so does the use of fat as food for the body. This allows for the body to use fat for its main energy source, decreasing the use of carbohydrate, and then could or should delay fatigue.

Endurance training is known to increase the amount of fat used as fuel.

A high fat diet is shown to elevate fat concentrations and mimic the same adaptation that is happening through training.

So how do you change your diet to increase fat as your main muscle fuel?

LCHF diets or “fat adaptation’’ is the consumption of a high-fat, low carbohydrate diet while undertaking normal exercise. Cutting out carbohydrates significantly can allow for fat to become an alternative energy source. Fat adaptation can be very powerful. One recent study in ultra-endurance athletes found that a high-fat diet burned up to 2.3 times more fat than carbohydrate in a 3-hour exercise session. After a period of 3–4 weeks the human body adapts to be able to use almost all fat for its fuel.

There are many ways to increase fat in the diet, but it is the type of fat that is the most important! All fats have the same amount of calories but they differ in their make-up. Good fats (monounsaturated and polyunsaturated fats) promote health benefits and are found naturally. Adding in good fats to your diet naturally will give increased health benefits, for example good fats improve cholesterol levels which can then reduce heart disease risk.

Here some quick tips to add in “good fats” into your diet:

Opt for snacks that are high in fat, like cheese, avocados, olives, seeds and nuts when feeling hungry.
If you want a treat, go for dark chocolate. With 9g of fat you won’t need that much dark chocolate to satisfy your craving.

Choose fatty fish like salmon which will make you feel full, but also provide you with omega 3 fats. These will help power your brain and also provide you with good fats.

Don’t allow yourself to ingest carbohydrate before or during exercise as it limits fat oxidation. The ingestion of 50–100 grams of carbohydrate in the hour before exercise will reduce fat oxidation by about 30–40%.

Other benefits shown with a high fat diet is the reduction in tissue damage and increases recovery rates. Also fat becomes an alternative energy source for the brain and supplies a stable amount of energy during endurance exercise. This leads to a decrease in the “hitting the wall” feeling, which many of us know can not be pleasant.
The limitation behind the high-fat diet is that fat may not be able to produce energy fast enough to meet the demands of the muscles. If fat is not produced at a fast enough rate and carbohydrate is limited, you will become tired quickly. Therefore high fat diets need to be carefully controlled to allow for right adaptations to occur to provide a benefit.

Main thoughts to take away from this blog:

The use of a high fat diet has the potential to benefit endurance athletes.

By increasing the amount of fat in the diet it also increases the amount of fat used in the muscle

High fat options include changing the oil you cook with, snacking on nuts, cheese or dark chocolate.

It has been shown to delay mental fatigue and also decrease the levels of injuries and enhance recovery.

There are limitations behind the theory but they have been shown to provide benefits to endurance athletes.

If you have any questions or would like more information about adding fat to your diet please feel free to contact Alice on nutrition@NZtrailrun.com.